In a list of Archaeological Acquisitions by the National Museum of Ireland in the year 1965; compiled by A. T. Lucas and published in the Journal of the Royal Society of Antiquaries of Ireland, volume 98, (1968), page 153 is what is suggested might be a Harpkey. With an acquisition number of 371 the description is given as;
image drawn from the National Museum of Ireland Archaeological Acquisitions in the Year 1965
Harpkey (?). bronze. From a crannog at Loughnaglack. Drummond Otra td. Co. Monaghan. Shaft is circular in cross section with a long point of square crosssection. Splayed fanlike head, ornamented with radial grooves along the wide edge. L. 16.5 cm; W. of head. 3.9 cm; D. of shaft. 5mm. and there is also a drawing of the item as figure 12.
It has to be assumed that whoever raised the possibility of this item being a harp key was somewhat unfamiliar with harps and keys as there is little likelihood that this could have been used to turn a tuning pin. The opposite end to the broad head comes down to a rather sharp point and is clearly designed for piercing, although probably not in the more usual twisting motion of a conventional awl.
This device was perhaps designed for making holes in leather prior to lacing sections together or may have been a medieval scribes tool used for pricking and lining velum. This was the technique which, through its use for marking velum prior to drawing a musical stave, led to the term to prick music meaning the act of writing down music. This in turn developed into prick song meaning the use of written music.